1. Field of the Invention
The present invention relates to an optical imaging lens assembly, and especially in a compact optical imaging lens assembly used in a portable electronic product.
2. Description of the Prior Art
In recent years, due to the popularity of compact photographing lens assembly, the demand for compact imaging modules is increasing, and the sensor of a general photographing camera is none other than CCD (Charge-Coupled Device) or CMOS device (Complementary Metal-Oxide Semiconductor Device). The pixel size of sensor component is reducing because of the advances in semiconductor manufacturing technology; meanwhile, electronic products are becoming more and more powerful yet featuring a compact design. Therefore, there is an increasing demand for better image quality of compact imaging lens assembly.
A conventional high-resolution imaging lens assembly generally adopts a lens assembly comprising four lens elements with a stop disposed at the front, wherein the first and second lens elements are mostly spherical glass lenses which are adhered together to from a doublet for correcting chromatic aberrations. The lens assembly disclosed in U.S. Pat. No. 7,365,920 serves as one such example; however, this kind of arrangement has the following disadvantages. First, the degree of freedom in arranging the lens system is curtailed due to the employment of excess number of spherical glass lenses; thus, the total track length of the system cannot be reduced easily. Second, the process of adhering glass lenses together is complicated, posing difficulties in manufacture. Moreover, as the size of imaging lens assembly is becoming smaller, assembling lens elements compactly within a limited space tends to cause unnecessary light rays which reflect too many times within a lens barrel that will affect image quality. Thus, to improve image quality, it is important to prevent unnecessary light rays from entering the image forming area.
Therefore, a need exists in the art for an optical imaging lens assembly applicable to compact, portable electronic products, wherein the lens assembly features better image quality, maintains a moderate total track length and has lower sensitivity of an optical system.